Single or multiple electric actuators are frequently arranged in a system and use a method with a microprocessor based controller that controls electrical power supplied to the electric actuator(s) to control extension and retraction of the actuator(s). The term “electric actuator” means electro-hydraulic actuator and/or electro-mechanical actuator. The term “electro-hydraulic actuator” means a self-contained actuator that converts electrical energy to hydraulic energy and applies the hydraulic energy to cause motion. A typical electro-hydraulic actuator, for example, includes an electric motor that drives a hydraulic pump to pressurize fluid from a reservoir and supply the pressurized fluid to a hydraulic cylinder or other hydraulic motor to cause motion. The term “electro-mechanical actuator” means a self-contained actuator that converts electrical energy to mechanical energy to cause motion. A typical electro-mechanical actuator, for example, includes an electric motor that drives a mechanical rod through a mechanism such as a screw thread to cause motion.
Such systems and methods are used in a wide range of stationary equipment and mobile equipment. One example of this type of system and method is used with mobile equipment to set and hold a platform for the equipment or other object in a predetermined attitude. The term “attitude” means the orientation or inclination of the axes of the object relative to a plane such as a horizontal plane or vertical plane, and the term “level attitude” means the orientation of the axes of the object in a plane substantially at a desired angle (including parallel) to a horizontal plane.
One example of such system and method used with mobile equipment is a leveling system and method used with motorized or towed recreational vehicles. Generally, when recreational vehicles are to be parked for an extended period of time, a set of leveling electric actuators are utilized to level and support the vehicle. Once the recreational vehicle is driven to the location where it will be parked, such as for example a campground or sporting event, the leveling electric actuators are engaged to raise the recreational vehicle and take much of the weight off of the vehicle's tires and to support the vehicle in a generally level attitude.